Environmental Systems Flashcards
How is cabin pressure controlled in a pressurized aircraft
More pressure than needed is pumped into the aircraft cabin, and the pressure controller modulates the outflow valve to maintain the correct pressure in the cabin
What is the function of the cabin outflow valve on a pressurized aircraft?
The cabin outflow valve, which is controlled by the pressure controller, maintains correct amount of pressure inside the cabin
What is the function of the cabin pressure safety valve on a pressurized aircraft?
The cabin pressure safety valve prevents cabin pressure from exceeding the maximum allowable differential pressure
Why must pressurized aircraft have a negative pressure relief valve?
The structure of an aircraft cabin is not designed to tolerate the inside pressure being lower than the outside pressure
What keeps the cabin of a pressurized aircraft from being pressurized when the aircraft is on the ground?
A squat switch on the landing gear holds the safety valve open when the aircraft is on the ground
What are three ways supplemental oxygen can be carried in an aircraft?
- As a high-pressure gas
- In its liquid form
- As a solid in the form of a chemical candle
What is the continuous-flow oxygen system?
An oxygen system that continuously flows a metered amount of oxygen into the mask
What is a pressure-demand oxygen system?
An oxygen system that flows oxygen to the mask only when the wearer of the mask inhales. Above a specific altitude, the regulator meters oxygen under pressure into the mask when the wearer inhales
Is there any special requirement as to the type of oxygen used in an aircraft system, and if so, what is it?
Only aviator’s breathing oxygen should be used
Describe the operating principle of a continuous-flow oxygen system
High-pressure oxygen flows from the storage cylinder to a pressure regulator where its pressure is reduced and then to the mask outlets whenever the system is turned on
Describe the operating principle of a pressure-demand oxygen system
Demand systems allow oxygen to flow from the cylinder to the regulator and then to the mask only when the user inhales. Pressure-demand systems provide oxygen to the mask at higher than atmospheric pressure when used at extremely high altitudes, forcing oxygen into the user’s lungs
What should be used to purge an oxygen system of moisture?
Oxygen, dry air, or dry nitrogen
What action must be taken when an oxygen system has been open to the atmosphere?
The system must be purged of any moisture
Describe the safety precautions that should be observed when servicing oxygen systems
Avoid all contact with petroleum-based oil or grease, don’t smoke, keep everything very clean, service systems outdoors if at all possible, and keep the caps on the bottles to protect the valves
What is a Roots blower?
A type of engine-driven compressor
